Hormonal evaluation of women who are suspected of having Polycystic ovary syndrome (PCOS) involves the measurement of basal levels of androgens and 17-hydroxyprogesterone (17-OHP), which are generally used to establish the presence of hyperandrogenemia. In general, these levels are obtained during the follicular phase to maintain sampling uniformity and avoid spurious increases due to corpus luteum function. However, because most hyperandrogenic patients are oligo/amenorrheic, it is frequently necessary to administer a progestogen to induce withdrawal bleeding and properly time the blood sampling.

Several medications have been described to properly induce withdrawal bleeding , with medroxyprogesterone acetate (MPA) being the most widely use. However, synthetic compounds as MPA do not replicate precisely the constellation of biologic activities of the parent hormone and results in a temporary, albeit clinically relevant, suppression in ovarian function and circulating androgen levels , in addition of several adverse side effects .

In this study, it is hypothesized that the administration of natural progesterone vaginally, which will avoid hepatic first pass, may result in significantly less hormonal suppression.

The authors test this hypothesis by prospectively determining the effect of vaginal micronized progesterone (OMP), administered for the induction of withdrawal bleeding, on the circulating androgen and 17-OHP levels in women with PCOS.

Inclusion Criteria:

• Chronic ovulatory dysfunction, defined as intermenstrual intervals of >45 days or a total of <8 menstrual cycles per year
• Polycystic ovaries, defined as at least one ovary with >12 follicles between 2 and 9 mm or an ovarian volume >10 mL
• Clinical hyperandrogenism, defined by a Ferriman Gallwey score >8

Exclusion Criteria:

• non-classic congenital adrenal hyperplasia,
• hyperprolactinemia
• thyroid dysfunction
• Oral contraceptives pills taken at least 3 months before the study